Circuit breaker



, 1934 2 Sheets-Sheet l lNvENToR CHARLES H. HODGKINS BY H15 ATTORNEYS March 9, 1937. c. H. HoDGKlNs CIRCUIT BREAKER rFiled Sept. 5

I March 9, 1937. C. H HQDGKlNS 2,073,104

CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed Sept. 5, 1934 70 zzz INVENTOR CHARLES H. HODGKINS BY HIS ATTORNEYS I 20 Y Another o Patented Maa* 9, 1937 .UNITED STATES 'PATENT OFFICE;

2,073,104 f CIRCUIT BREAKER' Charles H. Hodgkins, Fairfield, Conn., assigner to The Bryant Electric Company, Bridgeport, Conn., a corporation of Connecticut Application September 5, 1934, Serial No. 742,833

21Claims. (Cl. 20114-122) This invention relates' to circuit breakers. Moreparticularly it relates to`automatically operating circuit breakers which are released by the thermal and dynamic eiects of an overload current.

This invention is an improvement upon the inventionV disclosed' in my co-pending applications Ser. No. 683g6'73 led August 4th, 1933 and its d1`.

vision Ser. No. 706,564, led January 13, 193i.

It is an object of this invention to provide an automatic circuit breaker mechanism capable 'of being used within a casing of approximately the size and shape of `an ordinary screw type fuse D1 Another object is to provide a circuit' breakerl 'lof the type just mentioned -in which the contacts /may be manually closed and opened and which will .be opened automatically upon the occurrence.

of an overlog clnrent'in the' device.'

adapted particularly to use 'm a circuitfbreaker ofthe above mentioned type. f

Another object is to provide a circuit breaker of the above type with means for ventilation in order that the gases incipient upon' the 'oc- Acur'renee of an arc may be expeditiously and ef fectively condutedfromvthe casir'ig.H e

i Another object is to provide a"circult'lbreaker of the vaforementioned type whichfhas sufcient resistance in its parts to limit materially the cur the breaker. f 's A Another object is to provide means adjacent the contacts of the. circuit breaker of the above rent ow upon short circuit conditions through type which will protect the (sides of "the contacts and-assist in deionizing the are gases.

Other objectsand advantages o f my invention will occur as itis described in connection with' the accompanying drawings.

' In the drawings,

Y Fig. 1 is a :section view with' the section taken? along the of my improved circuit breaker,

the parts being in closed circuit position; Fig. 2 is 'a section view with the sectionpassingtransversely through the 4axis ,of my new circuit breaker fal'ong the line 2` 2 of Fig.4 1;

Fig.; a is a detail of the' middle ,magnetic ring j used in my circuit breaker; L

50. Fig. 4 is a plan view of my new'circuit breaker with the cover removed; y

Fig. 5 is a fragmentary view of the uppen part of my new circuit breaker, partly in elevation and partly in. section with the section passing 5 through the axis, the parts being in resetting position. Y

Fig. 6. is. a plan View of vmy new circuit breaker.

Referring to;` the drawingsklthe automatic circuit breaker mechanism is housed in. an insulat` ing casing I0 which in a general -Way resembles.

ect isto providearc extinguishing m'eans useful generally in circuit breakers but feature.

the size and shape of a conventional screw typev fuse plug. The casing is provided with a cover I2 .which is, rotatable upon the casing in order that a circular cam I4 which is formed integrally with the cover on the under side thereof, may 5 cooperate with one end l6e of a centrally pivoted lever I6 to cause engagement and disengagement of Ithe switch contacts I8 and I9 as will herein- 'after be more fully described.

Around the lower end of the casing there is a 10 conventional screw shell 20 which is adapted for screwing the device into a screw socket. ,I n the periphery of the casing I0 behind the screw shell there is a groove or a recess running circumfereentially half way. around the casing and havingv 15 seated in it a metal band 22 preferably-'madel of nichrome" alloy. vOne end of this band is riveted to the-'screw shell 20 by a rivet 24 and theI other end is riveted by a rivet 26 to the lower or, inner end of bimetallic strip 28 which extends 20 up toward the *top of the casing 'in a position parallel tothe axis of the casing but adjacent the V 'side wall thereof.- -At all points except-at the `rivet 25,*the metal band 22 is insulated from the screw shell 2l) by a sheetof insulation of any 25 suitable insulating material. The main 'functionf of this metal band is to heat the bimetal 28, it

beingvobvious that Athe band being of high re'v ysistance will suier a considerable temperature rise upon the passage of an cnlerload current 3o\ through-it.` Since the band ismetallically connected to the bimetal the heat from the band is conducted directly to the bimetal. The bimetal therefore need not be made so thin and so subject toburning as if theheat developed within the 35 bimetal 'by reason of its own resistance were vthe resistanceand Acuts down the current rise and it has beenffoundto be a valuable safety,

^ therewith' is a stationary contact I8 which is 5o 'generally cylindrical in shape and has ai rivet stem s2 passing through the bottom of the casi.

ing by which it is eeured m position. 'musstevtionaryn contact is imbeddeddn an annular piece of fibrous insulation 34 which'also has imbedded 55 in it a ring 36 of magneticmaterial such as iron, this ringi being coaxial of the contact andinsulatedatherefrom by means of the libre 341s Engaging with the stationarycoiitact I 8 is a movable contact le which. is generally cylindricalin 60 J' e9 `insulating' cup 44 while its top presses against the shape and is secured to a contact carrier 38 whose bottom'portion is in the formof aliollow cylinderl at the lower end of which the movable contact I8 is secured. At the central portion of thecontact carrierfaithee -projects a' circulan iiangeA or shoulder 40 from the edge of which depends a wall.

S2 which fits slidably within a cylindrical insulatin'g cup d4. Surrounding-the lower end of the lcontact carrier 38 and passing through the botl0 tom f the'insulating'cup 54 is a-ii'bre sleeve 66 which extends from just beneath thev ange or shoulder Si? half waydownthe side ofthe movable contact I9. L

It -has been foundA 'fby experiment that arcs' 15 which develop vbetween the.movable contact I 9 and the stationarycohtact i8 and play -upon the i fibre sleeve I6 and the annular nbre member 3Q/ cause gasesto be given out by theibre members vwhich tendto deiniz the-.arc gases and hence: 20 assist in'tlfe ealy extinguishment of the arc.

The top vpart of the contact carrier 33 consists of a'pir of parallel hollow semi-cylindrical arms jl i8 which extend up froml the shoulder or n ange 30 approximately the same distance as the lower 25. end of `the member 33 Aextends downwardly. The Vaxis 'of curvature of" these arms ,d3 is coaxial with Y the main axis of thedevice. "I n the arms 38 are a pair ofs'slots 50 in which slide/the ends .of a -shaft 521which is transverse to the general axis and causethe nose to 'againbeengaged under the lower edge of the plate 54 as ma readilybe seen in Fig. 5. Now uponI reversing the rotation lof the' cover vI2 the high point oi 'the cam will vain engag 'the en d Ie forcing' it down and 5 causing the lever It to pivot about the nose In which will causej engagement ofthe contacts as shownin Fig..i.. 4 J j In order to facilitate extinguishment g the arc ji'pon con't'act separation three;magn icrings -l0 preferably of iron and located in spaced parallel planesare employed. 'I'he position ofthe ring 36 has already been described. Another. ring @d is` positioned above the ring 36 and parallel to and isheldin such position by radial extensions Si which engage with the sidewall 'of the casing. This ring isalsoheld in place by'. its lower face resting upon .lugs or ribs 82 which extend out' from f s Athe inslde'of the casing at appropriate points. I

' Asia furthe means offnonnng the ring en mp0s: 2 0

tionv threeqcircular. projections 84V spaced equi f distantly from eachother and from the axis, pro Alect down from the bottom of the insulatingucup ess upon 'the upper surface, -f '^the 25 A third arc extinguishing ringN 86 @lso of iron o'r other magnetic material is'positined above the 'rings and lies adjacent the-bottomsurface o f the insulating cup .44. Thisring is held from upf,

ofthe whole device. Mounted upon this shaft 52 )Ward movement byjshecup and from 'downward 30f1 is the lever I6 which preferably is a metal stamping having-they shape illustrated inr'Ffg. ,-1, so that/its end Ide maybe engaged and moved by' the cam' I4, while its other end has a nose In which engages with the lower edge oi the plate 5% which` is secured Vto .the bimetallic.member'r The plate 541s insulated from the bimetallic member by suitable insulation anjd is riveted tothe' .bimetallic' member which also serves tojsecur 10- to the bimetallic member a terminal 66 infwlrich isen'gagecl one end of afiexible conductor 6% the other end of which is electrically connected to the i Hanse 4G ofthefcontact carrier., Y In order to provid lost motion between theV movable contact I9 and theA lever I8 there-isprovided afhelicalI spring 1liv within the lower end ofthe cgntatcarrier38.; 'This spring bears 'against the; bottom of the contactpcarrier and c against the'inder side of a member I'IZJwhse lower end `i cylindrical to slide within thecon .tact carrier `3B andswhose upper end comprises twovparallel arms-1 4. These armsslide within the arms BB of thecontact carrier and between them thelever itlJ is located,`the pivot shaftf5^-2- 55. ofthe lever I8 being journalled in the arms 'I4. -In rder to cause the contacts@ Separate with a jiap actiona helicalspring316is fitted'around the nbre sleeve 46 on the` contact carrier 38 and( -presses at its lower end upnf-the bottom o the under surface'ofthe finer 1 5- I J Referring now tovl li'lg.` 1 where the parts'. are 'S shown in closd circuit position.. it'willfbe ap-j 'parentthat upon an overload the bimetallic mem'- ber'will'heatv up 'and ilex towarthe walLoftliecasing thereby disengaging the nose Isn/of the' leverv I8V and 'aliowing the spring 1 6 to press "up" mthe'contact carrier 38 and separate the contacts.`

Now upon rotation of .the cover I2 of the casing [the low. point of the twill come around ad- ;'jacent the end I Be of the lever I aand atthe same .ftizne highpoigrt of the camwillpress against withefother.end/offthelever adjacentthe nose I Bn.

l an appropriate position. It will'be noted .that .portions @moves 99 Mf`-l`1tin the topfedg'e'o:

, 9| cut inthe'outside wall in the top'ofme casing -metal band 94 nts around thetop portion of the .movemnt by portio'ns ofits circumference resting `upon circumferential -shoulders l run-x f ningpartw'ay aroundV the inside ofthe casing at o f'the' circumferwv 35. ence of eachof the rings and 8B`dd not extend o ut'to the edge of' the casing and thus there ilsprovidednbetween the casingandthe c'ircumfer` ence of the rings-space for the'passage' of gases j incident Ato the amine on contact'sepersnon. 40' those gasescmaybe quickly removed from thevicinity ofthe arc and conducted quickly up to the top of the casing wherexthere is more room for them to expand.- To faoilitatefthelpa'ssase of these gases up tothe topiof the `casing the in^ 4.5

sulating cup Mas maybe seenin-Fig. 4 has a a pair of .proximate parallel ribsin its periphery- .running axially. On the/,opposite side of the cup 'from the ribs 'd5/are other ribs 41 also running axially thseribs seing wider. at tne-topths at so the. bottom-1.. Theutside's'urface 0 1 therc lletween thefribs las- 41 is cui: back to produce pas:

"sagesjii for the arc gases., 'I'hese-.passageswhile adequate for passage of the arc gases are .narrow v and compelY th/e gases to naiss in contact with the :cool walls ofthecup and casing so that th ir volume and temperature are reduced.inthel-L sage,'which is. vey `desirable. In order that the gasesmay` pass out from the casing? series of thacasing .60

beneath the cover I2 copera ting withy grooves agir; running in` a. direction parallel tothe cash :v a l. To. hold the ovefandcasing together aangedr Boff.

casing with the'ilange overlying theedge' of the 1 cover. The aro gases may pass out of the. casing.

through the passages s liandl vand exit therefrom by reasonofft Afait that the securing band. 94 does not .close- .of thesepssagesz s I n order tn .proteci'f the bimetallic `strip from theaction of the arc a baille 98 "ofinsu-v Y lating niaterialis seated in thebottom. part of the `casing adjacent; the lewe; end of the -.bime '.715'V y65' cover rand mechanism, means trg-.prevent holding said contacts closed manually onoverloach ther-- aortica tallic member and extends a suitable distance up the side of the casing adjacent the bimetallic member. It has been found that the deionizing leiect of the use of the nbre members about the furthermore-together with the'ven'tilation 'ofthe casing Amakes it possible for the' applicant with his new device to interrupt currents which heretofore it was impossible to interrupt with'any device ot equal size. I-n fact much larger devices have been necessary to handle continuously the currents which may be yhandled with ease by the device just described.v 'I'heimportance oi this will be apparent when itI is remembered' thatin' a device tobe used/in place oi' a fuse itis necessary to interrupt often very high current valuessu'sh/v as result when a short circuit occurs.

. Thus a device to be successful in this iieid'ot use must be capable of-inteijruptingI repeatedly v erating cover, switch mechanism, contacts operated by said cover and mechanism, means to prevent holding said contacts closed manuallyonoverload;thermally responsive means to operate said switch on overload, anda casing inwhich said parts are contained andare movable, said casing `havingsubstantially the size and shape `ofa conventional screw'type fuse' plug and having passages from the interior tothe exterior ofthe casing adjacent to said cover `for exit oi' arcgases. 4o 2. In-an electric switch, a rotatable switch operating Icover, switch mechanism; contacts operated by said cover and vent holding said contacts closed manually on overload, thermally responsive means to operate v saidswitch, on overload, and a casing. in which said parts are contained-andare' movable, said casing havingfsubstanti'ally the size and shape of av conventional screw type fuse plug and having l passagesin its beneath said cover conducting arc' gases iromthe casing.

50 necting with grooves in its outer suri'acefor con-" 3. In eating cover, switch mechanismfcontactsn' oper; atedby said cover and mechanism, means xto prevent holding -said contacts closed manually on.

. overload, thermally' responsive means to operate said switchen overload, amiga. casingin which said parts'arecontained'4 and are movable, said casing having 'substantially the size and shape of a conventional screw. type ius'e plug,`a rin'g member for-holding 'said cover to -said-ca's ing, said l r casing having passages trom the interior o f-jthe casing adjacent said ring for exit' of arc gases'.

switch mechanism; contacts operated by saide mally`responsive means for operatingsaid switch, on overload, a casing having substantially the size and having venting passages for the arc gases, and a plurality of rings of magnetic material for gare-quenching, said venting passages extending 'from said rings to' the extericr'of said casing.

5. In an electricy switch, a, rotatable cover,

switchj contacts I8 and la together with theiuse oi' the arc extinguishing rings 36,' 80 and 86 and y mechanism, neans to pre an electricswitcnpaotatable switch op- 4. In an electric" switch, a rotatable cover,;

and shape of a conventional screw type fuse plug switch mechanism, contacts operated by said cover and mechanism, means to'pevent holding I said contacts closed manually on overload, thermally responsive means for operating said switch onoverload, a casing having substantially'the size and shape oi avconventional screw type fuse plug .andfhaving venting passagesfor the arc gases, 'and a'plurality of rings of magnetic material for arc-quenching, said venting/passages kextending ifi-omy said rings to the vexterior of said casing, said 'contacts being surrounded by iibrous material over which an arc maypass and gen-'- erate deionizing gases.

6..,In 'an electric switch, a rotatable cover,

switch mechanism, contacts operated by said cover and mechanism,mean's to' prevent holding said contacts closed manually on overload, thermally responsive means for operating said switch .onl overload, a casing `size and shape of a conventional screw, type fuse plug and having venting passages to the exterior having substantially the j for the arc gases, said contacts being surrounded `by nbrous material over which an arc may pass and generate deionizing gases. l

'Ir In an electric switch, a rotatable cover,

switch. mecha contacts operated'by said cover and mechanism, means to prevent holding.

l said contacts closed manually' on overload, theron overloada casing having substantially the size and shape of a conventional screw type fuse V'plug andY having venting passages for the arcgases, 'and a plurality -of rings of magnetic material for arc-quenching, icertain ofy said Yrings lhaving portions cut away Afrom their'perip'heries to afford passages for the' movement of arc gases the casing.'

'8, In a switch, a-rotatable cover switch mechanism, contacts operated by said cover L and mechanism, means to prevent holding said conhigh resistance`connecting member non-fusible when traversed by. short circuit Vcurrents and connecting one oi' saidsocket members to said thermallyresponsive means for limiting the ,cur-

rent rise in said ldevice on shortv circuit condi- ",tions..

said contacts vclosed manually on overload, Lhermallyzr'esponsivemeansfor operating said switch on overload, a casingv havingsubstantially thel tacts closed during overload,"thermally responsive means for operating saidsswitc'h on overload, a casing f or said'switch,jsocket .contacts oh saidA casing i'or engaging said device in a socket, a'

. atm an electric switch. s. mamme covef switch mechanism, 'contacts *operated byA said ,A coverandmec anism, means` to prevent holding mally responsive meansior operating said switch into said venting passages; and to the outsidey of l A size and shape ofla conventional screw type fuse plug in which thev contacts and Aswitch mecha- 'n.ism arecontain'ed and moved,` said contacts being-surroundedf-by brous material over which an arcv may passand generate deionizing gases.

,10. In a ycircuitinterrupter, a casing, a stationary contact positioned adjacent one end of said casing,.a movable contact. actuable into and' out oi engagement with said stationarycontact, means providing'a Vventfrom said casing adjacent the 'vend opposite said stationary contact, a

member positioned within said casing adjacent the central portionstliereof, the .outerisurface of a large parto! said member extending along the inner surfaceoiI said casing at a-small distance therefrom providinga narrow passage extending iroxnthe contact-containing end to the other end of the casing, and the wall ot said passage deionizing the gases flowing therethrough.

amados y having a .large yarea of surface for cooling and `andbimetallic element in the 'circuit so thatthe t bimetalli'c element is caused -to bend upon the 11. In a circuit interrupter,` aoasing, arc eii- `occurrence of predetermined current conditions, tlnguishing means comprising atleast one metal and means for causing the opening of saidlpaii plate fitted within said casing adjacent one end of contacts upon the bending off saidbiinetallicl 5 thereof for extinguishing the`arc resulting duru element.A A s f ing circuit interruptiom said arc extinguiShing 1 7. In a circuit interrupter, a casinga pair of means having an opening extending there?l contactsgnsaid casing for opening-and closing through, means for interruptinga circuit in Said the circuit, Aa bime'tallic element extending lon-f Opening. means providing a Ventilating passage gitudinally along said casing aheater striptnen l0 between the outer edge of said `plate and Said. mally and electrically connected at one end to CaSingLa member Within Said Casing having its oneend" of said bimetallic element, said heater outer surface extending-along the inner surface strip extending oireumferentielly around said 0f Said Casing providing a narrow Passage from casing, means for connecting said heater strip Said Ventilating passage t0 Saidieid Ofithe KGa`S and bimetallic element in the circuit so that the'w15 ing With a large area of surface tocool and deb'imtallic element is caused to bend upon thel ionizev gases owing therethrough. occurrence` of predetermined current conditions.'

' 12. In acircuit breakerp a casing, stationary and means'vfor causing the opening of said pair L and movable Switch eontata, means 'fel' Causing of cntacts upon the bending of said bimetallic engagement and disengagement of said contacts, element.. said bimetaili'e element being located `520 means Providing a Yent freinaaid easing at an within said casing and said heaterstrip being end remotefrom Said Contacts, yineens within A iooeted around the outside of seid easing. f' Said Casing haVing-itS'Outer surfaeextending 18. Infa circuit breaker, a casing, stationary al0ng the inner Surfaee O f Said Casing Providing and movable svi/itch contacts; means for causing a nalrOW passage from the neighbihood 0f Said engagement and disengagement 'of' said contacts, 2 5

a large Surface area fm1 (2001318 and delonizing movement; an insulating sleeve around said 'mV-` arc gases.

Contacts'to Sad Vent means Said passage havingY means for guiding said movable contact inits A .Y i, Y l f able-contact for keeping the arc from playing 13. Ina circuit breaker',` a casing, AStatt-mary on the sides of" 'said movable contact and i931 and movable SWitCh OIltai-its,l means forcausing keeping the surfaces o'ffsaid contact in condi-l 30 engagement and disensasement'of said contacts, tion to siidefreeiy over seid guide means, seidmeans for guiding said-movable Contact in its sleeve extending from` nninediatel'y edjetent the movement, an insulating sleeve around said movable contact for keeping the arc from lplaying on the sides ors id movable contact and for keep` 19. In e. eirouit'breeker; dessine, stationery j ing the Surf e5 0f Seid Contact in tondition to and movable switch eontaets, .meens for causing Slide freely over Sad; glufie-lneans-4 .e Q engagement and disengagement of said contacts.

14- In a Circuit intglruiter, aOaSinS, a Stameans for'sguiding said movable contactin its.

tlOIiaiyOntaet member mounted thereinainovsv fmovement, aninsulating sleeve aroundsaid movable contact member havinga contact tip on one' fable dumb .for keeping the arc fromy playing` 40 ber, and means formed gf insulating'material and covering the portion of the "sides of' said movable saidguidmgg means.

, slide freely.

l of contacts 'in said-casing for openingand closend thereof, said movable contact memberi becontacting s L into said guiding"means,

on the sides'fof `said movable contact and fory keeping the surfaces of said'contac; -in/condilv tip into and Out'Ofbutt engagement With Said tion to-slide freely over vsaid guide means,- said( Stationary Contact meinbela guide 1n b eloinsleeve Vbeing carried by said movable contact and. sulating material'for said ,movable contact mem-7, fex'tedmg from immediately adjdcentthe con; 45; tacting 'surface up the sides of the contact into Contact 'member which Slides Within Seid guide 20.111 @circuit breaker, e sesingt stationery y nienlbel for. Preventing damage by the are Qi T and movable switch contacts, 'means for causing 50 Products t0 the SuIfaQeSn Sliding engagement engagement and". disengagement of said'con 50 andV forlkeepins 'Said"Su1flaCeS vin Candi-tionlto tactsfmeans forvv guiding said Jmovable' contact inits movement, aninsulatings/leev aroundsa'id movable contactior keeping the arc iroirrplay' ing' on the sides of `saideir'iovable cntactarid'for keeping 'the isurfacesofVv said contactv in condi- 55 1- tion to slidejfneely oversaid guide means; saidV 15.;In acircuit interruptere.casing; a'stag tionary contactadjacent to one end thereoLfa movable contact slidableinto and out of engage-' V ment with'said stationary Contact, guide means through which Said m0Vab1e`e0ntaet i$ .8lidable.,: sleevebeing carried by'said movable contact. said guide means t'ting closely around said mov: 21. In e eirouit interdpter, a easing, a. stal able contact and substantially preventing the. 'tiohgrj contactf member mounted." therein, 'a

W Of'are. produetabetween vSaid m0Vahle"C0n-' movable contact member 'having'a Acontact tiplii tact and Said elude meanslmeansiormins a pas' on one'end thereof, seid Amovttbie contact meme f 5,93 at Onalofmfe Points a'oliild the @ut'n pee( berf being sli'dable longitudinally to" bring said riphery of seid guide means to permit the new efontaet tip into and out of batt engagement with l `of arc products from. adjacent said.stationary` said'. stationary contactmembe'r, a guide member` vmutant t0 the other en d 0f Sad andA of insulating 'materiaivfor said`mo vab1e contaet lmember, and means formed of insulating mate-@ rial and covering, the portion of the siflesfof`said'f` `movable .contact member whichf'slides within `said guide xnemberfor prev ting 'damage by the products to the outside of said casing:

y 16. In a circuit interrupter, a casing, aC pair ing the circuit, a'bimetallic? elementy extending i vloi'igitudinally` alongsaid casing, a heater strip thermally and electrically connected at oneend -toV one endof said bimetallixgelementssaid heater strip extending Y circumierentially around i. saidcasing.l forcophectingsaidlieater stripfj gageme'nt and for keeping saidsurfaces in condditin to slide vfreelyfsaid llastnamed means -be'- ii'g4 carried by said movable contact. .l

arc "or arc'productstoethes Aaces inusliding en' 70| 

